A balloon catheter has been widely known as a medical device which widens a stenosed site formed in a living body. In recent years, a blade (elongated member) formed of a resin or metal having comparatively high rigidity has been proposed for installation on the outer surface side of the balloon of a balloon catheter. For example, Japanese Patent Application No. JP-A-2009-112361 discloses one type of balloon catheter with a blade installed on the outer surface of the balloon.
The balloon catheter provided with a blade as described above makes it possible to have the blade bite into the stenosed site (i.e., cut into the stenosed site) when the balloon is expanded while treating the stenosed site, and to perform treatment in which the stenosed site is widened while being cut into the blade (e.g., so that portions of the stenosed site are removed). For this reason, it is possible to exhibit a high treatment effect even in, for example, treatment of a lesion area (arteriosclerosis site or the like) in which calcification proceeds, or the like (i.e., the treatment method with the balloon catheter can be effective even when treating a lesion site that includes calcification).